Seed fall and flowering in white box (Eucalyptus albens Benth.) trees near Cowra, New South Wales

Abstract

Summary There are few studies of the factors affecting the recruitment of white box (Eucalyptus albens), a woodland tree of the inland slopes of south-eastern Australia with limited recruitment in recent times. One of these factors, seed fall, was monitored for periods ranging from 18 to 43 months (September 1995 to April 1999) at 14 E. albens trees in central western New South Wales. Seed collectors were located beneath the canopies of all trees and also outside the canopies at 12 of them. Flowering was also assessed — both visually and from the numbers of opercula in the collectors. Seed fall was highly variable between trees. Although one tree shed seed most of the time, and all those that were monitored for 43 months ultimately shed seed, there were lengthy periods when very little seed was collected. It appeared that most of the early-mature capsules present on all trees in mid-1995 did not shed seed until 1998. Seed fall beyond the canopy was low and from the limited data collected, it appeared that seed was evenly dispersed around the canopy. Flowering was similarly variable between trees, for example some produced abundant flowers every second year whereas others flowered in two or three consecutive years. However, averaged across all trees, flowering was abundant in 1997 and 1999 and was associated with above-average winter and spring rainfall in the previous year. Despite the presence of short-term seedbeds during the early period of monitoring and the absence of grazing at 12 of the trees, seedling recruitment was minimal during the 3.5 y of observation.